The present invention relates to surgical retractor apparatus. In particular, the present invention relates to a retractor apparatus that is attached to a retractor mounting apparatus.
Total hip replacement (arthroplasty) operations have been performed since the early 1960's to repair hip components. These components include the acetabulum (socket portion of the hip) and the femoral head (ball portion of the hip). The hip is typically replaced due to a gradual deterioration of the cartilage that cushions the bones within the joint. The surrounding structures in the hip begin to grow irregularly and can become inflamed and painful. Eventually, bone can begin to rub against bone causing severe discomfort.
Surgical procedures have been the most successful method to alleviate this pain. Either partial or total hip replacement surgery can be used. In total hip replacement, a cup shaped insert typically manufactured of polyethylene is inserted in place of the acetabulum, and a metal femoral head is placed in the femur. A number of variations have evolved in the surgical approaches and techniques used for replacement of the hip components, including operating while the patient is on his or her back (supine) or on his or her side (lateral). Additionally, the surgeon may perform an osteotomy of the greater trochanter portion of the femur which is reattached after insertion of the femoral insert. To a large extent, the choice of surgical approaches is due to the surgeon's preference as to what aspect of the hip components the surgeon wishes to view. The ability to view the surgical site is complicated by the need to remove the femoral head from the acetabulum as well as rotate and retract the femur in the wound during surgery.
The surgeon makes an incision along the hip and divides the tissue and muscle to expose the hip joint. The femoral head is removed from the acetabulum typically using a bone hook placed under the end of the femur proximate to the acetabulum. The femoral head is lifted out, along with flexing, adducting and internally rotating the hip. Typically, at least two strong people are needed to perform this part of the operation, since lifting and moving the leg can be a very strenuous activity that must be precisely performed. The proximal femur is then rotated upwardly into the wound using a broad flat retractor used as a lever which exposes the femoral head. The surgeon can perform the osteotomy of the femoral neck if desired. Using a retractor, the femur is retracted anteriorly and medially and rotated to provide acetabular exposure. The surgeon reams the acetabulum and places an acetabular implant into the acetabulum which is typically cemented in place.
To insert the femoral component, the proximal end of the femur is exposed. A common method to expose the femur is to rotate the femur so that the tibia is perpendicular to the floor. A broad, flat retractor is placed under the femur and the femur is levered upwards, out of the wound. The femoral component is then inserted. During this process, a pointed reamer is hammered into the femoral canal. A broach is inserted to enlarge the canal and a trial head is positioned within the canal. The hip is reducted (the femoral component is inserted into the acetabulum component) to check the angle and fit of the femoral head insert into the acetabulum insert. If the hip components do not adequately fit, the hip is again dislocated, the components adjusted, and the hip reducted. If the stability and placement of the trial inserts is acceptable, the hip is dislocated and the femoral implant stem is placed into the medullary canal of the femur. The hip is again reducted and the stability of the arthroplasty is confirmed. If the stability is questionable, the hip may again be dislocated, the components adjusted, and the hip reducted.
Due to the multiple dislocations and reductions, as well as retracting and rotating the femur, the surgical procedure can become quite physically taxing on the surgeon or surgeons performing it. The surgical procedure requires lifting and moving the patient's femur into multiple positions. At times, the surgeon may need to hold the femur in position for an extended period of time. Depending on the size of the patient, the strenuous activity can lead to fatigue and contribute to surgical error. Additionally, the repeated movement of the leg can cause nerve damage if it is not done precisely and with minimal adjustment. When the surgeon moves the femur by hand it is common to have continual adjusting occur. Often, the surgeon holding the leg, relaxes or becomes fatigued and allows the leg to move, requiring that the leg be readjusted. The movement can cause the leg to pinch tor rub nerves or muscle tissue, possibly causing damage.